A pair of such running devices is disposed on either side of a vehicle in the width direction, for instance, and is driven to cause the vehicle to run. The vehicle can turn by operating the running devices at different rotation speeds, for instance. A rubber crawler of such a running device provided for a vehicle has a smaller weight than a metal crawler and generates less running resistance and vibration, and is thereby used for a high-speed vehicle in general.
A type of rubber crawler, for instance, includes guide protrusions disposed at intervals on a center part, in the width direction, of an inner circumferential surface of a rubber elastic body formed into an endless shape, for preventing track rollers from falling off, and a pair of driving protrusions disposed at intervals on both sides, in the width direction, of the inner circumferential surface of the rubber elastic body, to engage with a sprocket. Such a rubber crawler does not have a metal reinforcement core material inside, and thus has less rigidity than a metal crawler.
In view of this, proposed is a rubber crawler provided with a plurality of steel cord rows extending in the circumferential direction of a rubber elastic body, and a plurality of bias cord rows extending diagonally at a predetermined angle from the circumferential direction of the rubber elastic body, disposed inside the rubber elastic body at least below the steel cord rows (see Patent Document 1). The steel cord rows reinforce a tension force that acts in the circumferential direction of the rubber elastic body, and the bias cord rows reinforce a force (e.g. torsion force) that acts in a sideway direction of the rubber elastic body.
A plurality of track rollers is disposed so as to be rollable on the inner circumferential surface of the rubber crawler. The track rollers absorb loads such as shock received from ground, and reduce vibration. Each track roller includes the first track-roller body part and the second track-roller body part, each having a disc shape, disposed to face each other and integrated over the guide protrusion in the width direction of the rubber crawler. The first track-roller body part is disposed between the guide protrusion and one of the pair of driving protrusions, while the second track-roller body part is disposed between the guide protrusion and the other one of the pair of driving protrusions. The track roller rolls on the inner circumferential surface of the rubber elastic body with the guide protrusion sandwiched between the first and second track-roller body parts.